webpack.prod.js

const { BundleAnalyzerPlugin } = require("webpack-bundle-analyzer");
const { merge } = require("webpack-merge");
const common = require("./webpack.common");

module.exports = merge(common, {
  mode: "production",
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: "/node_modules/",
        use: [
          {
            loader: "babel-loader",
            options: {
              presets: ["@babel/preset-env"],
            },
          },
        ],
      },
    ],
  },
  plugins: [
    new BundleAnalyzerPlugin({
      analyzerMode: "static",
      openAnalyzer: false,
    }),
  ],
  optimization: {
    splitChunks: {
      chunks: "all",
      minSize: 20000,
      maxSize: 70000,
      minChunks: 1,
      maxAsyncRequests: 30,
      maxInitialRequests: 30,
      automaticNameDelimiter: "~",
      enforceSizeThreshold: 50000,
      cacheGroups: {
        defaultVendors: {
          test: /[\\/]node_modules[\\/]/,
          priority: -10,
        },
        default: {
          minChunks: 2,
          priority: -20,
          reuseExistingChunk: true,
        },
      },
    },
  },
});